Conventional communication systems may be configured to support wireless terminals which utilize SLKs. The functions associated with such keys can be varied under control of a system switch or switch adjunct, such that the same physical key can represent multiple features at different times. This compensates for the typical lack of user interface. “real estate” on the wireless terminal by providing full feature access even with many fewer physical keys than, e.g., a corresponding wired terminal supported by the same system. A wireless terminal which incorporates SLKs generally includes a display containing the labels associated with the SLKs. In a conventional premises switching system, updates of these labels are typically explicitly controlled by the switch, e.g., based on predetermined functional modes associated with an operating context of the wireless terminal, and/or in response to commands entered by a user at the wireless terminal.
A significant problem with providing such a context-sensitive soft-labeled wireless terminal is that a number of run time misoperations or service degradations can occur if conventional command and update strategies are used to drive the wireless terminal. For example, if the system switch provides updates on a per-key-depression basis, the switch expends a considerable portion of its processing capacity in simply updating the label context of the SLKs on the wireless terminal. This is undesirable since it reduces system capacity, and since it introduces potentially unacceptable delays in updating the key labels. The latter difficulty may also lead to an interpretative misoperation. For example, assume the user depresses multiple SLKs at the wireless terminal. As a result, the switch sends a collection of updates to the terminal, and the first SLK update is processed and displayed. However, if the user then depresses another one of the SLKs, the switch has no way of knowing if all of the updates have been processed at the terminal, and therefore must impose interpretive assumptions about the terminal labels being displayed at the point in time when an SLK is depressed. This is an undesirable interpretive race condition, since the switch is mapping terminal button identifiers to system feature codes and the identifiers and codes may be desynchronized. Another problem associated with conventional control of SLKs is that a significant amount of bandwidth can be expended in the process of transmitting updates to the wireless terminal, thereby reducing the local radio access efficiency of the system.
Additional problems arise in conventional systems with regard to feature access control. The SLK display line in a terminal of such a system will generally present those features that are of the most use to the user in any given context. This in turn requires that the same area of the display present different features at different times, and in different contexts. For example, a terminal in an IDLE condition would have no use for a call management feature such as HOLD, while a feature such as a directory service would be of value. Therefore, the display must provide different SLK labels during different conditions. Also note that, depending on the service mode, the same system feature may be required in numerous contexts. For example, the HOLD feature may be of value during any incoming or outgoing call, and may also be of value during conferencing and transferring operations. This being the case, the HOLD feature will have four occurrences in a dynamically changing feature mix presented to the user via the SLKs. Conventional techniques are generally unable to provide efficient control of feature access. Such techniques may require an excessive number of multiple update transmissions from the serving switch to the terminal, thereby increasing the bandwidth required to support the terminal user interface.
A need therefore exists for techniques which allow a communication system switch to control SLKs of a wireless terminal user interface in a more efficient manner, while avoiding the run time misoperations and other problems associated with conventional techniques.